1. Field of the Invention
The present invention relates to the prevention of static buildup on polymeric materials by the addition of antistatic layers to those materials. In particular, the invention relates to antistatic coatings in association with imageable materials.
2. Background of the Art
Many different polymeric materials have been long recognized as suffering from electrostatic charge buildup during use. The problems associated with such static charging may be as modest as sparks from moving about on polymeric carpeting and popping sounds on phonograph records or as serious as memory erasure on computer disks and false artifacts in photographic film.
One usual method of reducing static buildup is the addition of a conductive layer or low surface resistivity layer to the polymeric article. It is common in the protection of shaped polymeric articles, including carpets, to treat the polymer with reactive or absorbable salts (e.g., U.S. Pat. No. 3,309,223 and 4,313,978). It is also known to form layers of inorganic metal oxides, either in film or particulate form to decrease the surface resistivity (e.g., U.S. Pat. Nos. 4,203,769 and 4,394,441). These antistatic coatings are known to be particularly desirable and useful as subbing layers in photographic articles (e.g., U.S. Pat. No. 3,874,879).
One other antistatic layer for photographic materials is described in EPO Application 0 301 827 A2 published Feb. 1, 1989 where a continuous gelled network of inorganic oxide particulates, including silica, are coated onto a substrate along with an ambifunctional silane to increase the wet adhesion of the antistatic layer to gelatin. These coatings tend to lose their antistatic properties when overcoated with a photographic construction because of penetration of gelatin into the pores of the layer.